CA1109355A - Liquid detergent composition - Google Patents

Abstract

Abstract of the Disclosure A liquid detergent composition, particularly suitable for use in the underbuilt region of dosages, comprises at least 10 % by weight of a sodium soap, at least 1 % by weight of an organic synthetic detergent, the wieght ratio of soap to synthetic detergent being 10:1 to 1:1, and at least 0.1 % by weight of a buffering agent.

Description

C 55L~/B 225 (~) The present invention relates to an aqueous liquid detergent composition comprising a mixture of a soap detergent and a non-soap detergent.
Aqueous liquid detergents are well~known in the art.
Usually such compositions contain one or more synthetic organic detergents, solvents, and, in the case of built aqueous liquid detergent compositions, inorganic and/or organic builder salts. Frequently, such compositions also contain hydrotropes, enabling the incorporation of sufficient quantities of detergent material and builder salts to attain the desired physical properties, as well as satisfactory detergency performance.
In formulating such aqueous liquid detergent compositions, physical properties like storage stability, clarity, viscosity, pourability etc. play an important role, as well as the detergency and foaming performance at a required volume usage of the composition. Thus, for example, while a particular composition may give satisfactory detergency and foaming performance at a given dosage, often a significant decline in performance is seen when lower dosages are used. This is particularly true in such situations where the dosage is insufficient to render the water-hardness ions inactive, i.e. in so-called "under-built" situations. From an ecological standpoint, the reduction of the amount of phosphate builder salts could bedesirable~ but such reduction causes a reduction in detergency performance, particularly in an underbuilt `

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situation.
It has already been proposed in the art to formulate so-called unbuilt liquid detergent compositions~ which are compositions which are free from builder salts. Thus, UK Patent Specification 1,370,402 discloses unbuilt liquid detergent compositions comprising a nonionic surfactant, an anionic surfactant which is an alkanolamine salt of Cg-Cl5 alkylbenzene sulphonic acid or o~ C8-C24 fatty aci.ds, further-more a free C8-C2L~ fatty acid and a solubilizing agent.
UK Patent Specification 1,365,46LI descrlbes unbuilt liquid detergents comprising a nonionic surfactant, a mixture of an alkanolamine salt of Cg-Cl5 alkylbenzene sulphonic acid and of C8-C24 ratty acids, and free ethanolamine.
These attempts are, however, not entirely satisfactory, as the attainment of one or more desirable characteristics frequently involves a significant reduction of other desirable properties. Thus, the above formulations may suffer from a too low foaming capacity, or from an inferior detergency at a higher dosage.
Furthermore, these formulations are directed to mixtures, in which the soap component is an alkanolamine salt, which is better soluble than the more readily available sodium soaps. The present invention is, however, directed to soap-based liquid detergent compositions, in which the soap component is or comprises a sodium soap.
Liquid detergent compositions, which may comprise a sodium soap, have indeed been proposed in the art. For example, US Patent Specification 2,875,153 discloses a `*'~

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-~ C 551l/~ 225 (R) liquid detergent composition in gel forrn, which contains a water-soluble soap and a nonionic detergent. The water-soluble soap can be a sodium soap. However, this product is a gel, which makes it unsuitable as a liquid detergent 5 composition in view of its viscosity and pourability characteristics.
US Patent Specification 2, 543,744 discloses a low-foaming dishwashing composition comprising an alkali metal soap, and a nonionic sur~actant. These formulations contain, when in the form o~ an aqueous liquld with a sodium soap, up to 7.5% of the latter.
Numerous other proposals have been made for liquid detergents containin~ a soap component. Thus US Patent Specification 3,723,328 refers to compositions 15 which may contain up to 16.2% of a sodium soap, and US
Patent Specification 3,707,503 discloses built compositions which may contain up to 4.5% of a sodium soap.
UK Patent Specification 1,415,719 discloses liquid compositions containing a liquid nonionic and fatty acids, which may be partially neutralized to form sodium soaps, and UK Patent Specification 1,081,556 discloses liquid detergent compositions in which part o~ the soap component may be a sodium soap.
Dutch Patent ~pplication 7413265 and ~erman Patent Application 2,411,528 relate to liquid compositions comprising a mixture of sodium soaps of C8-C14 saturated and C16-C22 unsaturated fatty acids, together with other, synthetic detergents and possibly builder salts.

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C 55ll / B 225 (R) Dutch Patent Application 740600ll discloses a liquid composition which contains up to 8% of an alkali metal soap, and up to 60% of a mixture of nonionic surfactants, and US Patent Specification 2,560,839 discloses a liquid composition containing up to 10% of an alkali metal soap, up to 30% of a nonioniG surfactant and up to 30% of a pyro-phosphate builder salk. Although all these attempts yield products which are suitable for certain launderinK purposes, they are less so for other cleaning operations, parkicularly at different dosages and/or in underbuilt situations.
It has now been found that satisfactory liquid detergent compositions can be obtained, which are isotropic, contain ecologically acceptable components, which are particularly suitable in the underbuilt region of dosages, but also show, at higher dosages, the superior detergency characteristics of built products over conventional unbuilt liquid composi'tions.
The discovery of such versatile compositions has been made possible by the use of high levels of fatty acid sodium soaps coupled with the incorporation of suitable levels of synthetic detergent and certain buffering agents enhancing the detergency performance of these liquid soap compositions.
The present invention therefore relates to an aqueous liquid detergent composition comprising, as essential ingredients:
a) at least 10% by weight of the composikion of a sodium soap of a straight- or branched chain C8-C24 fatty acid;

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~0~ C 55L~/ B 225 (R) b) at least l~o by weight of the composltion of an orgarlic synthetic - detergent, the weight ratio of' the soc~ um soap to the organic synthetic detergent being from 10:1 to 1:1;
c) at least 0.1% by weight of the composition of a buf'fering agent as 5 . hereina~ter defined.
Such aqueous liquid detergent compositions are effective at lower dosages in underbuilt situations, and are superior to other conventional unbuilt liquid compositions at higher dosages, where they may even behave as built liquids. The compositions of the inventlon have a superior performance at lower dosages when compared w:ith conventional built liquids at lower dosap,es.
The essential ingredients of the composition accordlng to the invention are discussed in detail below.
a. The soap component The soap component is or comprises a sodium soap of straight- or branched chain fatty acids with 8-24 carbon atoms in the alkyl residue. These fatty acids include saturated and unsatured natural fatty acids, as well as synthetic fatty acids. The latter may show some degree of branching in the alkyl residue, e.g. up to 20% methyl groups in the ~-position of the alkyl residue. Typical examples of suitable f'atty acids include ~aprilic-,capric-, lauric-, myristic-, palnitic-, stearic-, oleic-, linoleic-, behenic acid as well as mixtures of such fatty acids. Fatty acids, obtained from natural faks and oils are also suitable, such as coconut oil fatty acids, palm- and palm-kernel oil fatty acids, fatty acids derived f'rom soy~
bean oil, safflower oil, tall oil, tallow, ~ish oil, grease lard, groundnut oil, castor oil, and the like. Examples of synthetic fatty acids include those obtained by petroleum oxidation or by hydrogen-ation of carbon monoxide according to the Fischer Tropsch process.
The pre.erred, diu~ soaps are eodium oleate, sodium sa t o~

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~ ~ S C 55LI/ B 225 (R) coconut fatty acids and mixtures thereof. In the latter case,theweight ratioofthetwocomponents variesfrom 9:1 to 1:9, preferably4:1tol:4.
The minimum amount of the sodium soap to be present in the composition is about 10% by we;ght; the present invention enables the incorporation of high levels of sodium soap, i.e. up to 60% by weight of the sodium soap can be incorporated. In general, for most practical purposes the amount of thé sodium soap wi]l be from 15-50, particularly from 2~-35% by we~ight ofthecomposition.
Other soaps with a different; cation, such as potassium soaps, and alkanolamine soaps may also be incorporated, as long as the amount of sodium soap is within the ranges as given above.
The sodium soaps can be added to the compositions as such, or they can be formed in situ by neutralization of the corresponding fatty acids in the composition by means of the addition of a suitable sodium salt forming alkaline ; material, such as caustic lye and caustic soda. The same applies to the possibly co-used soaps with another cation.
b. The organic synthetic detergent.
This ingredient can be selected from the group consisting of anionic, nonionic, cationic, zwitterionic and amphoteric organic synthetic detergents. The anionic synthetic detergents (which term excludes salts of natural or synthetic fatty acids) are basically compounds with a hydrophobic radical and a solubilizing, salt forming anion, such as the sulphate, sulphonate, and phosphate anion.

~'' ' ' ' ' ., ~ , . , C 554/B 225 (R) Typical examples are C8-C18 straight- or branched chain alkylaryl sulphonates~ C~-C22 primary or secondary alkyl sulpha~es, C8-C22 primary or secondary alkane sulphonates, C8-C24 ~-olefin sulphonates, C8-C22 primary or secondary alkylether sulphates, containing from 1-15 moles o~ ethylene oxide, propylene oxide, butylene oxide or mixtures thereof, sulphonated fatty acids or fatty acid esters, C8-C24 acyltaurides, C8-C24 acylisethionates, C8-C18 alkyl-or alkylaryl phosphates or -ether phosphates with 1-10 moles of ethylene oxide, propylene oxide or mixtures thereof'.
Alkyl polyglycol ether carboxylic acid salts are a]so embraced by the term anionic synthetic detergents. Further examples of anionic synthetic detergents are described in standard text books, such as SchwartZ, Perry and Berch "Surface-active Agents and Detergents", Vol. I (~949) and Vol. II (1958). These anionics are used in the f'orm of their sodium-, potassium-, ammonium- or alkanolamine salt.
The nonionic synthetic detergents broadly embrace compounds having a hydrophobic radical and a water-solubilizing group which does not ionize. Normally this water-solubilization is effected by ethoxylation and/or propoxylation of a hydrophobic molecule, containing a removable proton.
Typical examples are the ethoxylation and/or propoxylation products of linear or branched-chain, primary or secondary, natural or synthetic alcohols having 8-24 carbon atoms in their alkyl chain, of mono- or dialkyl phenols having from 8-18 carbon atoms in their alkyl chain, : . , ` . - - ' : ~ -- . , ' ' C 55l~/B 225 (~) o~ C8-C22 f'atty acids (as defined f'or the sodium soaps herebefore), of polyethylene- or polypropyleneglycols, o~
C8-C22 fatty amines, f'atty am:ides or fatty alkylolamides etc. Further examples are given in the standard text book referred to above. By the non:ionic detergents are also to be understood the tertiary amine oxides having one alkyl chain with 8-18 carbon atoms and two alkyl chains with 1-5 carbon atoms, which may be substituted or ethoxylated; as well as sucrose esters.
Typical examples of cationic synthetic detergents are quaternary ammonium compounds such as the (di) higher alkyl di (lower) alkyl ammonium chlorides. Further examples are again given by the standard text book referred to above.
Zwitterionic synthetic detergents are for example the sulphobetaines such as alkyl dimethyl ammoniumpropane sulphonate, and amphoteric synthetic detergents are for example the mono- or dialkyl ~-amino carboxylic acids.
Examples of zwitterionic or amphoteric synthetic detergents are also disclosed in the standard text book ref'erred to above. Their salt forming cation may be a sodium, potassiurn, ammonium or an alkanolamine cation.
Naturally, mixtures of these synthetic organic detergents~ either of the same class or of a different class, may be used, e.g. a mixture of two diff'erent anionic or nonionic synthetic detergents, or a mixture of an anionic and a nonionic detergent. In general, at least 1% of the synthetic organic detergent should be present in the ; liquid composition. The maximum level can be as high as 50' by weight, and for most practical purposes the amount _g_ ~ C 55LI/B225 (R) varies from 5-40%, preferably f'rom 9-30% by weight.
The preferred synthetic detergents are the calcium-insensitive synthetic detergents, which have lime-soap dispersing properties, such as nonionics and alkylether-sulphates.
In general, the weight rat:io of the sodium soap to synthetic organic detergent is from 10:1 to 1:1 and, preferably~from 3:1 to 1:1.
c. The buffering agent.
The buffering agent of the invention can be an organic and/or inorganic source of alkalinity, exerting a buf'f'ering capacity to provide and maintain the wash liquor, prepared from the liquid detergent composition, at the appropriate pH-value, which i5 normally within the range from 7-11, preferably 8-10. The buffering agent can be a substance, which is simultaneously used to neutralize particular acid substances in the composition, and in that case an excess of the buffering agent should be used so as to provide for the minimum level of 0.1% by weight of free buffering agent to be present in the liquid composition.
The buffering agent can be an inorganic alkaline material such as NaOH, alkaline silicates, carbonates and metacarbonates, but preferab~y the buffering agent is an organic base such as morpholine, piperazine, and the alkanol-amines such as the mono-, di- and triethanolamines, the mono-, di-, and tripropanolamines and the mono-, di- and triisopropanol amines. Of these, the alkanolamines are preferred.Tri--ethanolamine is preferred for a low pH buffer, ' ' ' i . ' ~ ' ' C 55L~/B 225 (R) and mono-isopropanolamine for a high pH buffer.
At least 0.1% by weight of the buffering agent should be present, and the maximum level is about 20% by weight.
Normally from 1-15, and particuLarly from 2-10% by weight will be required for optimum properties.
The compositions Or the invention may furthermore comprise a number of non-essential, but often desirable, optional ingredients.
Thus, the compositions may comprise a solvent or a hydrotrope system. Such systems a1d in improving the physical properties of the composition, such as clarity, viscosity and phase stability. Solvents include the lower aliphatic alcohols, glycols and mono- or dialkylglycol-ethers, hydrocarbons, tetrahydrofurfuryl alcohol, and so on. The hydrotropes include sodium-, potassium-, ammonium-or alkylolamine salts of xylene-, toluene- and cumene-sulphonic acid, urea, mono alkane phosphonates and the like. Mixtures of solvents and hydrotropes may also be used.
In general, the amount of solvent or hydrotrope ranges from 0-10% by weight of the composition.
The composition may furthermore contain foam boosters such as the fatty acid alkylolamides, foam depressors such as sillcones, preservatives, anti-oxidantsg chelating agents, perfumes, fluorescers, colouring agents, germicides, bac-tericides, enzymes and enzyme-stabilisers, soil-suspending agents, anti-redeposition agents, opacifiers, electrolyte salts, such as alkali metal chlorides, -sulphates, -acetates C 55LI/B 225 (R) and the like.
All these further ingredients are normally used in minor amounts, e.g. in the order of 0.1~2% by weight.
As stated before, the liquid detergent compositions of ~he invention can be formulated into an unbuilt formulation, which ls preferred, but it is also possible to include builder salts therein. Any of the conventional organic and/or inorganic builder salts may be used, such as the phos-phate-type builder salts like sodium or potassium ortho-, pyro- or tripolyphosphate, furthermore salts of carboxy-methyloxysuccinate, calciumcarbonate, citrates, nitrilotri-acetic acid, sodiumaluminosilicates of the molecular sieve types, and other well-known builder salts. If builder salts are incorporated, the amount thereof may vary from 1-35%, and preferably 5-30% by weight of` the composition. In this respect it has also been found, that already small amounts of` a builder in these compositions give an improved detergency effect on cotton at 60C.
The compositions of the invention are particularly suitable for fabric washing, particularly of polyester/
cotton mixed fabrics, and they have shown to possess extremely good rinsing properties. They are isotropic liquids, having excellent physical stability under freeze/
thaw conditions.
The products of the invention can be made in any suitable manner, but it has been found advantageous to add the ingredients in such a sequential order that the sodium soaps are formed last, by in-situ neutralization. Thusg ,-.' ~ " .

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3~5i a preferred process consists of the following steps:
Add sequentially:
1. the fatty acids and melt these;
2. the fluorescer~ prePerably pre-dispersed in a nonionic surPactant;
3. preservatives;
Il. balance oP nonionic surfactant;
5. buPPer;
6. hydrotrope:
7. neutralizing agent as an aqueous solution;
8. water and perfume, iP desired.
The invention will now be Purther illustrated by way of Example.
Example I
The Pollowing clear isotropic liquid composition was prepared:
% by weight sodium oleate 17 sodium salt of coconut fatty acids 13 : C13-C15 primary alcohol, condensed with 7 moles of ethylene oxide 22 monoisopropanolamine 3 industrial methylated spirit 10 coconut Patty acid ethanolamide 2 fluorescer 1.0 ethylenediaminetetraacetic acid 0.1 ethanehydroxydiphosphonic acid 0.1 perfume 0.12 water balance This liquid was an isotropic liquid, having a freezing point o~ 3-4C.
Example II
, An isotropic liquid was prepared of the following composition:

C 55~/B 225 (R) % by wei~ht sodium oleate 8 sodium salt of coconut fatty acids 12 C13-C15 primary alcohol, condensed with 7 moles of ethylene oxide plus propylene oxide (weight ratio of Eo:Po=92:8) 15 triethanolamine 10 monoethyleneglycol 10 fluorescer ~ dye o L~
water balance This liquid was clear and re~ained stable over prolonged periods of storage at temperatures between -5 and-~50C.
Example III
The following isotropic liquid was prepared:
% by weight sodium oleate 12.5 sodium salt of coconut fatty acids 12.5 secondary linear Cll-C15 alcohol, condensed wlth 9 moles of ethylene oxide 20 C16-C18 linear primary alcohol, condensed with 3 moles of ethylene oxide, sulphated (sodium salt) 5 monoethylene glycol 10 triethanolamine, ethanol . 5 water balance C 554/B 225 (R) A~,~,,,,r~

Examp e IV
The ~ollowing built liquid was prepared:
_ ht sodium oleate sodium salt o~ coconut ~atty acids 6 C12-C15 alcohol, condensed with 9 moles o~ ethylene oxide 5 sodium linear C12 alkylbenzenesulphonate 9 tetrapotassiumpyrophosphate 14 tetrasodiumpyrophosphate monoethanolamine 2 water balance Example V
: The ~ollowing unbullt liquid detergents were prepared:
. ~ by weight A B C D
sodium oleate 22.7 17 17 10 sodium salt ofcoconut ~atty acids 17.3 13 13 10 C13-C15 alcohol, condensed with 7 moles of ethylene oxide 5 ~ 14 14 sodium alkylether sulphate - 9 sodium alkylbenzene sulphonate - - 8 sodium C14_15 alkylSulPhate - ~ 6 ~ triethanolamine 5 5 - 5 : monoisopropanolamine - 3 3 industrial methylated spirit 15 10 10 10 ~luorescer preservative 0.2 0.2 water balance balance balance balance C 551~/B 225 ~

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Example VII
-The liquid of Example I was compared in Tergotometer washing experiments with a product according to UK Patent Specification 1,365,464, containing 33% of a nonionic, 12% of an anionic and 10. 5% triethanol amine as the basic system. The washes were carried out in water of 6FH at about 25C, using 1 kg of 50% soi~dloads for 8 minutes, folIowed by three rinses. The detergency was measured using ERTC 41 A
and AS 12 test pieces, and fluorescence and redeposition were measured using non-fluorescent cotton pieces. The products were used at concentrations oE 0.7, l.o, 1.5 and 2.0 g/l.
The detergency results (reflectancy) were as follows:

ct conc. 0.7 l.o 1.5 2.0 I
test cloth ~ Ex.1 Contr. Ex.1 Contr. Ex.1 Contr. Ex.1 Contr.
. . , ERTC 41 A 67.5 68 7o 7o 73~5 71 74 5 71.5 `~ AS 12 52 52 56 53.5 60 56 63 56 L

~; The product of Example 1 was superior especially at higher dosages.
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Claims (7)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. An aqueous liquid detergent composition comprising (a) from 10-60 % by weight of a sodium soap of a fatty acid having from 8 to 24 carbon atoms in its alkyl residue;
(b) from 1-50 % by weight of an anionic, nonionic, cationic, zwitterionic or amphoteric organic synthetic detergent, whereby the weight ratio of (a):(b) is from 10:1 to 1:1; and (c) from 0.1-20 % by weight of an organic buffering agent selected from the group consisting of the ethanol-,propanol- and iso-propanol amines.

2. A composition according to claim 1, comprising 15-50 % by weight of (a) 5-40 % by weight of (b) and 1-15 % by weight of (c).

3. A composition according to claim 2, comprising 20-35 % by weight of (a) 9-30 % by weight of (b) and 2-10 % by weight of (c).

4. A composition according to claim 1, wherein the weight ratio of (a):(b) is from 3:1 to 1:1.

5. A composition according to claim 1, wherein (a) is selected from the group consisting of sodium oleate, sodium salt of coconut fatty acids and mixtures thereof, (b) is selected from the group consisting of nonionic synthetic detergents and alkylether-sulphates, and (c) is selected from the group consisting of triethan-olamine and monoisopropanolamine.

6. A composition according to claim 1, further comprising from 1-35 % of a water-soluble organic or inorganic builder material.

7. In a process for making an aqueous liquid detergent composition according to claim 1, the step forming the soap last, by in situ neutralization of the fatty acid.